119Sn Mössbauer spectroscopic insight into the effect of surface-located tin dopant cations on the visible-light photocatalytic activity of anatase TiO2

The presence of Sn⁴⁺ dopant ions on the surfaces of titania crystallites results in a nearly fourfold increase in the rate constant of a white-light photocatalytic bleaching reaction of methyl orange. Thus, the positive effect of a Sn^II electronic lone pair, which was theoretically predicted in 2013 by Iwaszuk and Nolan for a SnO-nanocluster modified anatase model, can be experimentally revealed using catalyst powders containing surface-located oxidized Sn⁴⁺ species.